8 Things That Happen to Your Body During Sex

Ever wondered what happens to your body during a steamy session between the sheets? From the good (happy hormones! increased sensitivity!) to the not-so-good (increased risk of urinary tract infections, for example), here are eight things that happen when you're having sex.

1. Happy hormones are released. Sex stimulates the secretion of hormones such as oxytocin, which makes you feel connected to others, and dopamine, which activates the brain’s reward center. The result: You feel satisfied and close to your partner.

2.Blood vessels widen. What do dilated blood vessels do for you? “Your clitoris and vulva become engorged, as do the vessels in the vaginal wall,” says urologist and sexual-health expert Jennifer Berman, MD. “This leads to more secretions and lubrication.” Your face and chest can also get flushed.

3.Sensitivity skyrockets. Your erogenous zones, including the nipples, ears, neck, and genital area, become extra sensitive because of increased blood flow and the release of sensation-enhancing neurotransmitters.

4.Bacteria may build up. During sex, bacteria from the vagina and anus can get into the urethra and multiply, leading to a urinary tract infection. Tip: Pee immediately after the act to flush out bacteria.

5.You burn (some) calories. A study in The New England Journal of Medicine found that a 154-pound person would burn 21 calories during six minutes of sexual activity. So a roll in the sack isn’t as effective as spin class, but a sexy half hour could torch around 100 calories.